Chapman attended Cambridge University to study medicine, where he began writing comedy with classmate John Cleese. The duo wrote professionally on the BBC during the 1960s, primarily for the ubiquitous David Frost[?] but also for Marty Feldman.
They joined Michael Palin, Terry Jones, Eric Idle and American artist Terry Gilliam for Monty Python's Flying Circus in 1969. Cleese and Chapman's classic Python sketches included "The Ministry of Silly Walks" and "The Dead Parrot". A particularly famous sketch character of his was The Colonel, a stuffy army officer who occasionly appeared out of nowhere to order the end of a sketch for being too silly. After Cleese left the show in 1973, Chapman wrote alone for the final season. He then developed a number of movie scripts, most notably Yellowbeard in which he starred with Cleese, Peter Cook, and Cheech and Chong.
His memoir, A Liar's Autobiography, was published in 1980. Chapman joined the Dangerous Sports Club, which introduced bungee-jumping to a wide audience, and he went on lengthy college lecture tours in the 1980s. In the fall of 1989, he died on the eve of the 20th anniversary of Python's debut, of throat cancer which had spread (metastasized) to his spine. His eulogy, delievered by Cleese, was perhaps the first one in which the word "fuck" was used, and some people at the funeral almost died laughing. Cleese has said that Chapman would have liked that.
Chapman was in many ways the loneliest Python member. He endured years of excessive drinking which nearly killed him in the 1970s, and he also kept his homosexuality a secret for much of his adult life. The remaining Python members have acknowledged that Chapman was exasperating to work with, and difficult to know. But none of the other Pythons could have played King Arthur or Brian as well as Chapman, and with his, death speculation of a Python revival inevitably faded.